ASMAX-1 is a CQUAM compatible Stereo, or Mono capable AM Medium Wave DDS-based (better than PLL stability) radio broadcast board for educational or similar use that offers great audio quality, 1KHz frequency step selection (for both 10KHz US and 9KHz EU steps) using only four keys. You connect audio and send it wirelessly using whip antenna, distance varies with surrounding conditions, RF PEP output 100mW [according to US FCC Part 15.219] or 400mW PEP [EU] (at 50 Ohm) maximum over the entire band. FULL BROADBAND DESIGN, no variable caps to adjust! Reception is on a regular AM radio set anywhere from 530KHz to 1700KHz (special model available for 510-2000KHz covering 160m band) and minimum step of 1KHz.

It has two independently adjustable audio inputs, for Left and Right channels with modified 50usec or 75usec pre-emphasis and low-pass filtering (depending on country).

You can change the broadcast frequency on the fly using incremental speed tuning. Just press the UP or DOWN button to go up or down the frequencies. After ENTER is pressed the DDS is re-programmed with the new transmission frequency. The power-on frequency and all other settings can be saved to the built-in non-volatile memory at the press of a key.

The unit meets all FCC (Part-15) requirements for AM transmitters. It has an excellent spectral purity with harmonics rejection better than -50dBc (upper half band) as can be seen in a Spectrum Analyser, out-of-band spurious output better than -60dBc, and accuracy of the lock-on frequency better than +/- 0.5Hz. You can manually turn the RF output on/off, or use the built-in real-time clock to set a daily or weekend schedule for automatic on/off at a specific time. With this option, one can leave the unit at a remote site and have it operate only for the specified hours.

A C-QUAM Stereo encoding system is built-in and provides crystal clear audio up to 15KHz and with a channel separation of more than 35dB. Optionally, this system can be de-activated via a menu selection in case you need to use the device as a Mono AM transmitter.